Gun perforator



Patented Feb. 17, 1948 UNITED STATES PATENT OFFICE Applicatiogllllailf, girl-:50. 670,781

1 The invention relates to a gun perforator, and particularly to a perforator in which the several guns are set off by the detonation of an explosive charge. 9

It has been found that in gun perforators of the type which are loaded and lowered into a well bore for the purpose of setting off the bullets to penetrate the casing or earth formations, that a great deal of danger is involved due to the arrangement and construction of the parts which causes premature explosions.

The present invention contemplates a unit gun barrel which can be inserted as a final operation as the gun is lowered into the well bore. and also provides for an efilcient mode oi conducting the initial detonation to the several guns spaced along the perforator so as to insure the firing of all of the bullets.

It is one of the objects of the inventionto provide agun barrel having a plurality of longitudinally spaced gun barrels therein, and wherein a booster detonating charge is position between the respective guns.

Another object of the invention is to provide an annular recess about the gun barrel in a gun perforating tool and thenconnecting adjacent recesses with a passage having a booster detonating charge therein.

. Still another object of the invention is to A provide a composite gun barrel and explosive container adapted to be inserted in a gun barrel as the last operation prior to the lowering of the gun barrel into the well.

Still another object of the invention is to pro-' vide a composite structure made up of an explosive chamber with a gun barrel threaded and sealed therein to be inserted in the perforator tool body as a unit so that in tightening and loosening of such unit. there will be no frictional engagement whatsoever with the explosive charge.

Still another object of the invention is to seal a unitary explosive unit and gun barrel in a gun perforator body. 4

Other and further objects of the invention will be readily ap arent when the following description is considered in connection with the accompanying drawings in which:

Fig. l is an elevation of a gun barrel arranged and constructed in accordance with the inven- I of this sort of a plurality of sections and any desired number of such sections may be coupied together. Very often as many as sixty firing charges are embodied in a single tool.

The tool may be lowered into the well bore in any desired manner such as by a wire line or by a string of pipe 6. The lower end of the tool is usually rounded as at i so as to guidethe tool in its movement.

In Fig. 2 the sections 8 and 9 of the body are threaded together at in and a seal ring ll provided to maintain a seal between the two body parts.

The body 9 is shown as having been provided with the cavities ll, two of which are shown and which are illustrated as facing in opposite directions and spaced longitudinally along the body portion 9. Each of these cavities is provided with an enlarged annular recess l5 intermediate the ends of the cavity so that when the firing unit I! is threaded at l8 into the cavity. an annular space 20 will be thus provided as defined by the recess i5 and the periphery 2| of the firing unit.

The firing unit is a cylindrical body having the explosive receiving chamber 25 therein and having an inlet conduit 25 leading from the recess 20 into the explosive chamber 25 so that the explosive in the chamber may be fired.

The body 8 has the passage 30 therein and aligned with this passage is an opening 3| which "receives the primer cap 82. Any suitable member may be dropped through the pipe 30 so as to strike the primer 32 and effect the detonation thereof.

The fire from this primer cap moves into the recess 20 and into the conduit 28 to fire the explosive charge. The recess 20 conducts this fire around the firing unit i! to the lower portion of the recess l5 and into the booster charge passage 34. -An explosive booster charge 35 is .disposed in and extends transversely across this .c to the explosive chamber. and the gun barrel 4| is threaded therein. The gun barrel is made up of the hollow barrel 42 which receives the bullet 43 and the sealing member 44. The bullet may be of the pointed cylindrical shape as seen in 45 or it may have the boat tail effect as shown ii the boat tail bullet is used the base of the barrel will be tapered at 41 as seen in Fla. 3 to receive the base of the bullet.

A suitable sealing disk 48 may be disposed at the end of the gun barrel to position it with respect to the firing charge. The firing unit has the spanner wrench openings 50 therein by which it may be firmly screwed into position.

In the operation of these guns of this type it will be remembered that they are lowered into a well bore filled with a column of liquid,v that depths of from ten to fifteen thousand feet are reached in the drilling of wells so that static pressures up to as high as eight or ten thousand pounds per square inch may be encountered. The parts must be firmly sealediin order to resist such tremendous pressures and to this end the seals ii are arranged between the firing units and the body.

The explosive charge placed in the explosive chamber 25 must be of considerable size in order to cause the bullet 43 to penetrate the steel casing and often times considerable cement has been placed therearound.

With other types of gun perforators it has been the practice to place the explosive charge in the perforator tool and to then screw the gun barrel in on top of such charge. There have been many accidents due to the friction against the explosive charge caused by such operation and the present gun contemplates that the firing unit will be made up prior to the use of the gun so that the gun barrel ll may be screwed into position in the firing unit without causing friction against.the explosive charge due to the provision of the disk 48 on the one hand, and it may be screwed in in the shop where the operator can readily protect himself should there be an accidental explosion. Then, this firing unit, completely assembled, can be carried as a separate unit and placed in the gun barrel as the last operation as it is lowered into the well bore. This last operation would merely constitute the threading of the firing unit into the threads IS with the explosive charge completely enclosed and subjected to no frictional action. A substantial safety feature is thus provided which protects the operator because the tool can be lowered through the equipment on the derrick into the casing.

Broadly the invention contemplates a perforating gun which is explosively fired and where booster charges are arranged to conduct the fire from one firing unit to the other and wherein the firing units are installed as one of the last operations in preparing the gun for use.

The invention claimed is:

l. A gun perforator including, a body, said body having formed therein a plurality of lateral cavities at spaced longitudinal intervals, a removable firing unit in threaded position in each cavity, an annular enlargement formed substantially centrally of each cavity, said body peripherally contacting saidunit at either side of said enlargement so that the body and the unit define an annular space about the unit, an axial passage in said.body joining the enlargements of successive cavities, and means for successively firing said units, including a primer in said passage above the uppermost of said enlargements, a booster charge in each axial passage portion intermediate successive enlargements, and a propellant charge in each of said units in communication with the surrounding annular enlargement.

2. A gun periorator including, a body. said body'having formed therein a plurality 0! lateral cavities at spaced longitudinal intervals, a removable firing unit in threaded position in each cavity, an annular enlargement formed substantially centrally of each cavity, said body peripherally contacting said unit at either side of said enlargement so that the body and the unit define an annular space about the unit. an axial passage ln said body joining the enlargements of successive cavities, and means for successively firing said units, including a primer in said passage above the uppermost of said enlargements, a booster charge in each axial passage portion intermediate successive enlargements, and a propellant charge in each of said units, there being in each unit a conduit connecting the propellant charge with the surrounding annular enlargement.

3. A gun perfcrator including, a body, said body having formed therein a plurality of lateralcavities at spaced longitudinal intervals, a removable firing unit in threaded position in each cavity, an annular enlargement formed substantially centrally of each cavity, said body peripherally contacting said unit at either side of said enlargement so that the body and the unit define an annular space about the unit, an axial passage in .said body joining the enlargements of successive cavities, and means for successively firing said units, including a primer in said passage above the uppermost of said enlargement, a booster charge in each axial passage portion intermediate successive enlargements, and a propellant charge in each ofsaid units, there being in each unit a conduit connecting the propellant charge with the surrounding annular enlargement, said conduit being displaced sidewardly from the axis of said passage.

4. A gun perforator including, a body, said body having formed therein a plurality of lateral cavities at spaced longitudinal intervals, a removable firing unit in threaded position in each cavity, an annular enlargementformed substantially centrally of each cavity, said body peripherally contacting said unit at either side of said enlargement so that the body and the unit define an annularspace about the unit, an axial pasf 'sagein said body joining the enlargements of successive cavities, and means for successively firing said units, including a primer in said passage above the uppermost of said enlargements, a booster charge in each axial passage portion intermediate successive enlargements, and a propellant charge in each of said units, said booster charges being transversely co-extensive with said successive cavities, and means for successively firing said units,-including a primer in said passage above the uppermost of said enlargements, a booster charge in each axial passage portion intermediate successive enlargements, and a pro- Queue pellant charge in each of said units, sald booster charges being transversely co-extensive with aald mums passage to secure the sequential nring of said Number Name Date charges, there being in each unit a ccndult eon- 3.395534 Colllnl Sept. 15, 1942 nectlng the propellant charge with the surround- 2,328.24! Alexander Aug. 3!. 19 3 in: annular enlargement. said oohdult helng dls- 2.351.179 A101 J ne 1 1 placed aldewardly from the axis of said passage. 2,891,032 'Iurechek Jan. 1. 1048 We!!! cn'm 3 The following references are of room! in the flloolthienatent: 

